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The testing estimation processThe testing estimation processBy Antonio Cardoso

In my opinion, one of the most difficult and critical activities in IT is the estimation process.I believe that it occurs because when we say that one project will be accomplished in a

such time by a such cost, it must happen. If it does not happen, several things may follow:from peers’ comments and senior management’s warnings to being fired depending on thereasons and seriousness of the failure.

Before even thinking of moving to Systems test at my organization, I always heard from thedevelopment group members that the estimations made by the Systems test group weretoo long and expensive. Then, when I arrived at my new seat, I tried to understand thetesting estimation process.

The testing estimation process in place was quite simple. The inputs for the process,provided by the development team, were: the size of the development team and the

number of working days needed for building a solution before starting systems tests.

The testing estimation process said that the number of testing engineers would be half of the number of development engineers and one third of the number of development workingdays.

A spreadsheet was created in order to find out the estimation and calculate the duration of tests and testing costs. They are based on the following formulas:

Testing working days = (Development working days) / 3.

Testing engineers = (Development engineers) / 2.

Testing costs = Testing working days * Testing engineers * person daily costs.

As the process was only playing with numbers, it was not necessary to register anywherehow the estimation was obtained.

To exemplify how the process worked, if one development team said that to deliver asolution for systems testing it would need 4 engineers and 66 working days then, the

systems test would need 2 engineers (half) and 21 working days (one third). So, thesolution would be ready for delivery to the customer after 87 (66+21) working days.

Just to be clear, in testing time, it was not included the time for developing the testcasesand preparing the testing environment. Normally, it would need an extra 10 days for thetesting team.

The new testing estimation processThe new testing estimation process

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All estimation should be based on previous projects. If a new project has similar requirements from a previous one, the estimation is based on that project.

44thth Rule: Estimation shall be based on metricsRule: Estimation shall be based on metrics

My organization has created an OPD, Organization Process Database, where the projectmetrics are recorded. We have recorded metrics from three years ago obtained fromdozens of projects.

The number of requirements is the basic information for estimating a testing project. Fromit, my organization has metrics that guide us to estimate a testing project. The table belowshows the metrics used to estimate a testing project. The team size is 01 testing engineer.

Metric Value

1 Number of testcases created for each requirement 4,53

2 Number of testcases developed by Working day 14,473 Number of testcases executed by Working day 10,20

4 Number of ARs for testcase 0,77

5 Number of ARs verified by Working day 24,64

For instance, if we have a project with 70 functional requirements and a testing team sizeof 2 engineers, we reach the following estimates:

Metric Value

Number of testcases – based on metric 1 317,10

Preparation phase – based on metric 2 11 working daysExecution phase – based on metric 3 16 working days

Number of ARs – based on metric 4 244 ARs

Regression phase – based on metric 5 6 working days

The testing duration is estimated in 22 (16+6) working days. Plus, 11 working days for preparing it.

55thth Rule: Estimation shall never forget the pastRule: Estimation shall never forget the past

I have not sent away the past. The testing team continues using the old process and thespreadsheet. After the estimation is done following the new rules, the testing teamestimates again using the old process in order to compare both results.

Normally, the results from the new estimate process are cheaper and faster than the oldone in about 20 to 25%. If the testing team gets a different percentage, the testing teamreturns to the process in order to understand if something was missed.

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